Pileus Git - ~andy/linux/blob - drivers/media/v4l2-core/videobuf2-dma-contig.c

   1 /*
   2  * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  *
   6  * Author: Pawel Osciak <pawel@osciak.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation.
  11  */
  12
  13 #include <linux/dma-buf.h>
  14 #include <linux/module.h>
  15 #include <linux/scatterlist.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/dma-mapping.h>
  19
  20 #include <media/videobuf2-core.h>
  21 #include <media/videobuf2-dma-contig.h>
  22 #include <media/videobuf2-memops.h>
  23
  24 struct vb2_dc_conf {
  25         struct device           *dev;
  26 };
  27
  28 struct vb2_dc_buf {
  29         struct device                   *dev;
  30         void                            *vaddr;
  31         unsigned long                   size;
  32         dma_addr_t                      dma_addr;
  33         enum dma_data_direction         dma_dir;
  34         struct sg_table                 *dma_sgt;
  35
  36         /* MMAP related */
  37         struct vb2_vmarea_handler       handler;
  38         atomic_t                        refcount;
  39
  40         /* USERPTR related */
  41         struct vm_area_struct           *vma;
  42
  43         /* DMABUF related */
  44         struct dma_buf_attachment       *db_attach;
  45 };
  46
  47 /*********************************************/
  48 /*        scatterlist table functions        */
  49 /*********************************************/
  50
  51
  52 static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
  53         void (*cb)(struct page *pg))
  54 {
  55         struct scatterlist *s;
  56         unsigned int i;
  57
  58         for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
  59                 struct page *page = sg_page(s);
  60                 unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
  61                         >> PAGE_SHIFT;
  62                 unsigned int j;
  63
  64                 for (j = 0; j < n_pages; ++j, ++page)
  65                         cb(page);
  66         }
  67 }
  68
  69 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
  70 {
  71         struct scatterlist *s;
  72         dma_addr_t expected = sg_dma_address(sgt->sgl);
  73         unsigned int i;
  74         unsigned long size = 0;
  75
  76         for_each_sg(sgt->sgl, s, sgt->nents, i) {
  77                 if (sg_dma_address(s) != expected)
  78                         break;
  79                 expected = sg_dma_address(s) + sg_dma_len(s);
  80                 size += sg_dma_len(s);
  81         }
  82         return size;
  83 }
  84
  85 /*********************************************/
  86 /*         callbacks for all buffers         */
  87 /*********************************************/
  88
  89 static void *vb2_dc_cookie(void *buf_priv)
  90 {
  91         struct vb2_dc_buf *buf = buf_priv;
  92
  93         return &buf->dma_addr;
  94 }
  95
  96 static void *vb2_dc_vaddr(void *buf_priv)
  97 {
  98         struct vb2_dc_buf *buf = buf_priv;
  99
 100         return buf->vaddr;
 101 }
 102
 103 static unsigned int vb2_dc_num_users(void *buf_priv)
 104 {
 105         struct vb2_dc_buf *buf = buf_priv;
 106
 107         return atomic_read(&buf->refcount);
 108 }
 109
 110 static void vb2_dc_prepare(void *buf_priv)
 111 {
 112         struct vb2_dc_buf *buf = buf_priv;
 113         struct sg_table *sgt = buf->dma_sgt;
 114
 115         /* DMABUF exporter will flush the cache for us */
 116         if (!sgt || buf->db_attach)
 117                 return;
 118
 119         dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 120 }
 121
 122 static void vb2_dc_finish(void *buf_priv)
 123 {
 124         struct vb2_dc_buf *buf = buf_priv;
 125         struct sg_table *sgt = buf->dma_sgt;
 126
 127         /* DMABUF exporter will flush the cache for us */
 128         if (!sgt || buf->db_attach)
 129                 return;
 130
 131         dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
 132 }
 133
 134 /*********************************************/
 135 /*        callbacks for MMAP buffers         */
 136 /*********************************************/
 137
 138 static void vb2_dc_put(void *buf_priv)
 139 {
 140         struct vb2_dc_buf *buf = buf_priv;
 141
 142         if (!atomic_dec_and_test(&buf->refcount))
 143                 return;
 144
 145         dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
 146         kfree(buf);
 147 }
 148
 149 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
 150 {
 151         struct vb2_dc_conf *conf = alloc_ctx;
 152         struct device *dev = conf->dev;
 153         struct vb2_dc_buf *buf;
 154
 155         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 156         if (!buf)
 157                 return ERR_PTR(-ENOMEM);
 158
 159         buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
 160         if (!buf->vaddr) {
 161                 dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
 162                 kfree(buf);
 163                 return ERR_PTR(-ENOMEM);
 164         }
 165
 166         buf->dev = dev;
 167         buf->size = size;
 168
 169         buf->handler.refcount = &buf->refcount;
 170         buf->handler.put = vb2_dc_put;
 171         buf->handler.arg = buf;
 172
 173         atomic_inc(&buf->refcount);
 174
 175         return buf;
 176 }
 177
 178 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 179 {
 180         struct vb2_dc_buf *buf = buf_priv;
 181
 182         if (!buf) {
 183                 printk(KERN_ERR "No buffer to map\n");
 184                 return -EINVAL;
 185         }
 186
 187         return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
 188                                   &vb2_common_vm_ops, &buf->handler);
 189 }
 190
 191 /*********************************************/
 192 /*       callbacks for USERPTR buffers       */
 193 /*********************************************/
 194
 195 static inline int vma_is_io(struct vm_area_struct *vma)
 196 {
 197         return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
 198 }
 199
 200 static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
 201         int n_pages, struct vm_area_struct *vma, int write)
 202 {
 203         if (vma_is_io(vma)) {
 204                 unsigned int i;
 205
 206                 for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
 207                         unsigned long pfn;
 208                         int ret = follow_pfn(vma, start, &pfn);
 209
 210                         if (ret) {
 211                                 pr_err("no page for address %lu\n", start);
 212                                 return ret;
 213                         }
 214                         pages[i] = pfn_to_page(pfn);
 215                 }
 216         } else {
 217                 int n;
 218
 219                 n = get_user_pages(current, current->mm, start & PAGE_MASK,
 220                         n_pages, write, 1, pages, NULL);
 221                 /* negative error means that no page was pinned */
 222                 n = max(n, 0);
 223                 if (n != n_pages) {
 224                         pr_err("got only %d of %d user pages\n", n, n_pages);
 225                         while (n)
 226                                 put_page(pages[--n]);
 227                         return -EFAULT;
 228                 }
 229         }
 230
 231         return 0;
 232 }
 233
 234 static void vb2_dc_put_dirty_page(struct page *page)
 235 {
 236         set_page_dirty_lock(page);
 237         put_page(page);
 238 }
 239
 240 static void vb2_dc_put_userptr(void *buf_priv)
 241 {
 242         struct vb2_dc_buf *buf = buf_priv;
 243         struct sg_table *sgt = buf->dma_sgt;
 244
 245         dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 246         if (!vma_is_io(buf->vma))
 247                 vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
 248
 249         sg_free_table(sgt);
 250         kfree(sgt);
 251         vb2_put_vma(buf->vma);
 252         kfree(buf);
 253 }
 254
 255 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 256         unsigned long size, int write)
 257 {
 258         struct vb2_dc_conf *conf = alloc_ctx;
 259         struct vb2_dc_buf *buf;
 260         unsigned long start;
 261         unsigned long end;
 262         unsigned long offset;
 263         struct page **pages;
 264         int n_pages;
 265         int ret = 0;
 266         struct vm_area_struct *vma;
 267         struct sg_table *sgt;
 268         unsigned long contig_size;
 269
 270         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 271         if (!buf)
 272                 return ERR_PTR(-ENOMEM);
 273
 274         buf->dev = conf->dev;
 275         buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 276
 277         start = vaddr & PAGE_MASK;
 278         offset = vaddr & ~PAGE_MASK;
 279         end = PAGE_ALIGN(vaddr + size);
 280         n_pages = (end - start) >> PAGE_SHIFT;
 281
 282         pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
 283         if (!pages) {
 284                 ret = -ENOMEM;
 285                 pr_err("failed to allocate pages table\n");
 286                 goto fail_buf;
 287         }
 288
 289         /* current->mm->mmap_sem is taken by videobuf2 core */
 290         vma = find_vma(current->mm, vaddr);
 291         if (!vma) {
 292                 pr_err("no vma for address %lu\n", vaddr);
 293                 ret = -EFAULT;
 294                 goto fail_pages;
 295         }
 296
 297         if (vma->vm_end < vaddr + size) {
 298                 pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
 299                 ret = -EFAULT;
 300                 goto fail_pages;
 301         }
 302
 303         buf->vma = vb2_get_vma(vma);
 304         if (!buf->vma) {
 305                 pr_err("failed to copy vma\n");
 306                 ret = -ENOMEM;
 307                 goto fail_pages;
 308         }
 309
 310         /* extract page list from userspace mapping */
 311         ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, write);
 312         if (ret) {
 313                 pr_err("failed to get user pages\n");
 314                 goto fail_vma;
 315         }
 316
 317         sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 318         if (!sgt) {
 319                 pr_err("failed to allocate sg table\n");
 320                 ret = -ENOMEM;
 321                 goto fail_get_user_pages;
 322         }
 323
 324         ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
 325                 offset, size, GFP_KERNEL);
 326         if (ret) {
 327                 pr_err("failed to initialize sg table\n");
 328                 goto fail_sgt;
 329         }
 330
 331         /* pages are no longer needed */
 332         kfree(pages);
 333         pages = NULL;
 334
 335         sgt->nents = dma_map_sg(buf->dev, sgt->sgl, sgt->orig_nents,
 336                 buf->dma_dir);
 337         if (sgt->nents <= 0) {
 338                 pr_err("failed to map scatterlist\n");
 339                 ret = -EIO;
 340                 goto fail_sgt_init;
 341         }
 342
 343         contig_size = vb2_dc_get_contiguous_size(sgt);
 344         if (contig_size < size) {
 345                 pr_err("contiguous mapping is too small %lu/%lu\n",
 346                         contig_size, size);
 347                 ret = -EFAULT;
 348                 goto fail_map_sg;
 349         }
 350
 351         buf->dma_addr = sg_dma_address(sgt->sgl);
 352         buf->size = size;
 353         buf->dma_sgt = sgt;
 354
 355         return buf;
 356
 357 fail_map_sg:
 358         dma_unmap_sg(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 359
 360 fail_sgt_init:
 361         if (!vma_is_io(buf->vma))
 362                 vb2_dc_sgt_foreach_page(sgt, put_page);
 363         sg_free_table(sgt);
 364
 365 fail_sgt:
 366         kfree(sgt);
 367
 368 fail_get_user_pages:
 369         if (pages && !vma_is_io(buf->vma))
 370                 while (n_pages)
 371                         put_page(pages[--n_pages]);
 372
 373 fail_vma:
 374         vb2_put_vma(buf->vma);
 375
 376 fail_pages:
 377         kfree(pages); /* kfree is NULL-proof */
 378
 379 fail_buf:
 380         kfree(buf);
 381
 382         return ERR_PTR(ret);
 383 }
 384
 385 /*********************************************/
 386 /*       callbacks for DMABUF buffers        */
 387 /*********************************************/
 388
 389 static int vb2_dc_map_dmabuf(void *mem_priv)
 390 {
 391         struct vb2_dc_buf *buf = mem_priv;
 392         struct sg_table *sgt;
 393         unsigned long contig_size;
 394
 395         if (WARN_ON(!buf->db_attach)) {
 396                 pr_err("trying to pin a non attached buffer\n");
 397                 return -EINVAL;
 398         }
 399
 400         if (WARN_ON(buf->dma_sgt)) {
 401                 pr_err("dmabuf buffer is already pinned\n");
 402                 return 0;
 403         }
 404
 405         /* get the associated scatterlist for this buffer */
 406         sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
 407         if (IS_ERR_OR_NULL(sgt)) {
 408                 pr_err("Error getting dmabuf scatterlist\n");
 409                 return -EINVAL;
 410         }
 411
 412         /* checking if dmabuf is big enough to store contiguous chunk */
 413         contig_size = vb2_dc_get_contiguous_size(sgt);
 414         if (contig_size < buf->size) {
 415                 pr_err("contiguous chunk is too small %lu/%lu b\n",
 416                         contig_size, buf->size);
 417                 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 418                 return -EFAULT;
 419         }
 420
 421         buf->dma_addr = sg_dma_address(sgt->sgl);
 422         buf->dma_sgt = sgt;
 423
 424         return 0;
 425 }
 426
 427 static void vb2_dc_unmap_dmabuf(void *mem_priv)
 428 {
 429         struct vb2_dc_buf *buf = mem_priv;
 430         struct sg_table *sgt = buf->dma_sgt;
 431
 432         if (WARN_ON(!buf->db_attach)) {
 433                 pr_err("trying to unpin a not attached buffer\n");
 434                 return;
 435         }
 436
 437         if (WARN_ON(!sgt)) {
 438                 pr_err("dmabuf buffer is already unpinned\n");
 439                 return;
 440         }
 441
 442         dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
 443
 444         buf->dma_addr = 0;
 445         buf->dma_sgt = NULL;
 446 }
 447
 448 static void vb2_dc_detach_dmabuf(void *mem_priv)
 449 {
 450         struct vb2_dc_buf *buf = mem_priv;
 451
 452         /* if vb2 works correctly you should never detach mapped buffer */
 453         if (WARN_ON(buf->dma_addr))
 454                 vb2_dc_unmap_dmabuf(buf);
 455
 456         /* detach this attachment */
 457         dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
 458         kfree(buf);
 459 }
 460
 461 static void *vb2_dc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 462         unsigned long size, int write)
 463 {
 464         struct vb2_dc_conf *conf = alloc_ctx;
 465         struct vb2_dc_buf *buf;
 466         struct dma_buf_attachment *dba;
 467
 468         if (dbuf->size < size)
 469                 return ERR_PTR(-EFAULT);
 470
 471         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 472         if (!buf)
 473                 return ERR_PTR(-ENOMEM);
 474
 475         buf->dev = conf->dev;
 476         /* create attachment for the dmabuf with the user device */
 477         dba = dma_buf_attach(dbuf, buf->dev);
 478         if (IS_ERR(dba)) {
 479                 pr_err("failed to attach dmabuf\n");
 480                 kfree(buf);
 481                 return dba;
 482         }
 483
 484         buf->dma_dir = write ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
 485         buf->size = size;
 486         buf->db_attach = dba;
 487
 488         return buf;
 489 }
 490
 491 /*********************************************/
 492 /*       DMA CONTIG exported functions       */
 493 /*********************************************/
 494
 495 const struct vb2_mem_ops vb2_dma_contig_memops = {
 496         .alloc          = vb2_dc_alloc,
 497         .put            = vb2_dc_put,
 498         .cookie         = vb2_dc_cookie,
 499         .vaddr          = vb2_dc_vaddr,
 500         .mmap           = vb2_dc_mmap,
 501         .get_userptr    = vb2_dc_get_userptr,
 502         .put_userptr    = vb2_dc_put_userptr,
 503         .prepare        = vb2_dc_prepare,
 504         .finish         = vb2_dc_finish,
 505         .map_dmabuf     = vb2_dc_map_dmabuf,
 506         .unmap_dmabuf   = vb2_dc_unmap_dmabuf,
 507         .attach_dmabuf  = vb2_dc_attach_dmabuf,
 508         .detach_dmabuf  = vb2_dc_detach_dmabuf,
 509         .num_users      = vb2_dc_num_users,
 510 };
 511 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
 512
 513 void *vb2_dma_contig_init_ctx(struct device *dev)
 514 {
 515         struct vb2_dc_conf *conf;
 516
 517         conf = kzalloc(sizeof *conf, GFP_KERNEL);
 518         if (!conf)
 519                 return ERR_PTR(-ENOMEM);
 520
 521         conf->dev = dev;
 522
 523         return conf;
 524 }
 525 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
 526
 527 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
 528 {
 529         kfree(alloc_ctx);
 530 }
 531 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
 532
 533 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
 534 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
 535 MODULE_LICENSE("GPL");